1. Field of the Invention
The present invention generally relates to the manufacture of springs, and, in a preferred embodiment thereof, more particularly relates to a method for machining the opposite end surfaces of a coiled compression spring in a manner such that the end surfaces will be precisely parallel to one another when the spring is axially compressed to a predetermined loaded length thereof.
2. Description of Related Art
Under conventional practice, the opposite end surfaces of a coiled compression spring are ground square, with the spring at its free or relaxed length, prior to placing the spring in an operating environment in which the spring is axially compressed to a working or loaded length between two opposing, parallel planar surfaces. This machining technique often results in spring end surfaces that are not precisely parallel to one another when the spring is ultimately compressed to its loaded length.
In turn, this nonparallel spring end surface relationship typically creates lateral deflection forces in the compressed spring which undesirably cause it to bend at least slightly to one side, thereby degrading the desired force/deflection linearity of the spring.
Traditional methods of compensating for this heretofore unavoidable lateral deflection of the compressed spring have been to react the lateral spring deflection force against a fixed object, or to add additional components to the overall spring installation that will not transmit the spring side load. The first compensation method undesirably adds friction to the assembled spring structure, while the second compensation method undesirably adds structural complexity to the overall spring assembly.
It can readily be seen from the foregoing that it would be desirable to provide an improved method for machining the opposite end surfaces of a coiled compression spring in a manner such that when the spring is compressed to its loaded length between a pair of opposing, parallel planar surfaces the machined spring end surfaces will be precisely parallel to one another to thereby essentially eliminate undesirable lateral deflection of the axially compressed spring. It is accordingly an object of the present invention to provide such a method.